How to Choose a Natural Gas Compressor for Different Pressure and Flow Requirements?

Choosing a compressor for a natural gas project starts with two basic questions: How much gas needs to be compressed, and from what pressure to what pressure? The answers determine the compressor capacity and pressure range required for the job. Other factors, such as gas conditions, cooling, lubrication, control, and installation, then help narrow down the right model.

Bengbu Kery Compressor Co., Ltd. has more than 20 years of experience in gas compressor R&D and manufacturing. Its equipment is used in oil and gas, gas stations, chemical energy, steel, geothermal, and other industrial applications.

Natural Gas Compressor Models for Different Pressure and Flow Requirements

Kery offers several natural gas compressor models for different operating conditions. The published specifications cover relatively small gas flows as well as large-capacity applications, with different inlet and outlet pressure ranges.

The range is quite broad. Some models are designed for low gas flow, while others handle several thousand cubic meters per hour. Outlet pressure also varies considerably between models. This makes the actual project requirements more important than simply choosing a compressor with the highest capacity.

1. Check the Required Gas Flow First

Gas flow is one of the first specifications to confirm when selecting a natural gas compressor.

The compressor needs enough capacity to handle the normal gas demand and, where necessary, short periods of higher demand. Buying a unit that is too small can limit the gas supply. On the other hand, a much larger unit may cost more to purchase and may not run efficiently when the actual gas demand is low.

Before comparing models, buyers should have a clear figure for:

• Normal gas flow
• Peak gas flow
• Continuous or intermittent operation
• Expected changes in gas demand
• Required operating margin

Kery’s product range gives a good example of how different the capacity requirements can be. The ZW-0.2/1-18 is listed at 20 Nm³/h, while the MFWD-3.5/(16-78)-81 has a flow range of 3,000–17,000 Nm³/h.

The suitable capacity depends on the application. It is usually better to select a model that works comfortably within the required operating range than to focus only on its maximum flow rate.

2. Compare Inlet and Outlet Pressure

After determining the flow rate, look at the pressure requirement.

A compressor may have the right flow capacity but still be unsuitable if it cannot provide the required pressure increase. The basic figures to confirm are:

Inlet pressure → Outlet pressure → Required flow

For example, a gas source operating at a relatively low pressure may need a compressor for initial boosting. A CNG application or high-pressure gas process will have very different requirements.

The specifications on Kery’s product page show this difference clearly. The ZW-0.65/0.12-0.5 is listed with an inlet pressure of 0.012 MPaG and an outlet pressure of 0.05 MPaG. By comparison, the DF-1.25/3-250 has an inlet pressure of 0.3 MPaG and an outlet pressure of 25 MPaG.

This is why flow rate and pressure should always be checked together.

3. Match the Compressor to the Application

The operating conditions are different from one natural gas project to another, so the compressor should be selected with the end use in mind.

Oil and Gas Production

Natural gas produced during oil and gas operations may need to be boosted before transportation, processing, storage, or further treatment. The available gas pressure and required downstream pressure are important when selecting the equipment.

Gas Pipeline Transportation

Pipeline systems need a stable gas supply at the required pressure. The compressor therefore needs to provide the required pressure increase while being suitable for long operating periods.

CNG Stations

CNG stations normally require higher compression pressures than ordinary gas boosting applications. The compressor selection should take into account the incoming gas pressure, required filling pressure, station capacity, and expected operating frequency.

Industrial and Chemical Applications

Natural gas may be used as a process gas or fuel in industrial facilities. In these cases, stable gas delivery and compatibility with the production process are important considerations.

Kery lists oil and gas development, pipeline transportation, city gas supply, chemical production, gas stations, gas power generation, industrial furnace fuel supply, associated gas recovery, and underground gas storage among the applications for its natural gas compressors.

4. Consider Efficiency When Comparing Models

Energy use becomes an important issue when a compressor runs for long hours.

A high efficiency natural gas compressor should be matched to the actual pressure and flow requirements rather than selected simply because it has a higher rated capacity. An oversized compressor does not necessarily mean better performance. If the operating point is far from the actual gas demand, the extra capacity may provide little practical benefit.

When comparing equipment, look at:

• Compression ratio
• Gas flow
• Operating hours
• Cooling system
• Lubrication arrangement
• Load changes
• Maintenance requirements

The compressor unit is only one part of the system. Kery’s product information also identifies the power system, cooling system, lubrication system, and control system as important parts of a complete gas compression setup.

5. Check the Control System

Control requirements are another point worth checking, especially for systems that operate continuously or need closer supervision.

An intelligent natural gas compressor can be useful when operators need to monitor operating conditions and manage the equipment with less manual intervention.

Depending on the project, useful control functions may include:

• Pressure monitoring
• Operating status monitoring
• Automatic protection
• Alarm functions
• Start and stop control
• Parameter display
• Connection with other plant control systems

For a small installation, a simple control arrangement may be enough. Larger gas compression systems may benefit from more comprehensive monitoring and automatic control.

6. Pay Attention to Cooling and Lubrication

Gas compression produces heat, particularly when the pressure increase is large. The cooling arrangement should therefore match the compressor’s operating conditions and installation environment.

Lubrication is also worth checking before selecting a model. Kery’s published specifications include oil-free and less-oil configurations for different natural gas compressor models.

The choice should be based on the actual gas, pressure range, operating conditions, and requirements of the downstream process. There is no need to assume that one lubrication arrangement will suit every application.

7. Consider the Installation Environment

A compressor may have suitable pressure and flow specifications but still require a different configuration because of the installation site.

Before placing an order, check:

• Available installation space
• Indoor or outdoor installation
• Ambient temperature
• Cooling conditions
• Noise requirements
• Gas safety requirements
• Skid-mounted or fixed installation
• Access for maintenance

For field projects, a compact or skid-mounted configuration can make transportation and installation easier. In a permanent industrial facility, the compressor may need to connect with existing piping, electrical equipment, cooling systems, and plant controls.

8. A Practical Selection Process

A straightforward selection process can help avoid common mistakes.

Step 1: Confirm the gas conditions

Check the gas composition, temperature, inlet pressure, and other relevant conditions.

Step 2: Determine the flow rate

Calculate the normal and peak gas demand in Nm³/h.

Step 3: Set the pressure target

Confirm the required outlet pressure and the pressure increase needed.

Step 4: Shortlist suitable models

Remove models that cannot meet either the flow or pressure requirement.

Step 5: Compare the configuration

Look at cooling, lubrication, drive, control, and installation requirements.

Step 6: Consider future demand

If gas consumption is expected to increase, leave reasonable room for future operation without choosing an unnecessarily large unit.

This process makes model comparison much easier and helps keep the selection tied to the actual project.

9. Flow and Pressure Should Be Considered Together

One common mistake in compressor selection is focusing on only one specification.

A compressor with sufficient flow but inadequate outlet pressure cannot meet the process requirement. A unit capable of much higher pressure may also be unnecessary if the application only requires a small pressure increase.

A useful comparison can be made with the following points:

Looking at these factors together gives a clearer picture of which compressor is suitable for the job.

FAQ

Conclusion

The right compressor is determined by the actual gas conditions rather than by capacity alone. Flow rate, inlet pressure, and outlet pressure should be established first, followed by cooling, lubrication, control, installation, and future demand.

For a small gas supply, a compact compressor may be sufficient. Larger pipeline, recovery, CNG, or industrial applications may call for a higher-capacity model. Energy consumption and control requirements should also be considered when comparing equipment. A properly matched high efficiency natural gas compressor can help keep operating costs under control, while an intelligent natural gas compressor can make monitoring and day-to-day operation easier.

With more than two decades of experience in gas compressor manufacturing and R&D, Kery provides natural gas compression equipment for oil and gas, industrial, chemical, energy, and other applications. Its range of models allows buyers to select equipment according to the pressure and flow requirements of the actual project.